package v1ch08.genericReflection;

import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.util.Arrays;
import java.util.Scanner;

/**
 * @author Cay Horstmann
 * @version 1.10 2007-05-15
 */
public class GenericReflectionTest {
	public static void main(String[] args) {
		// 从命令行参数或用户输入读取类名
		String name;
		if (args.length > 0) name = args[0];
		else {
			try (Scanner in = new Scanner(System.in)) {
				System.out.println("Enter class name (e.g. java.util.Collections): ");
				name = in.next();
			}
		}
		
		try {
			// 打印类和公共方法的通用信息
			Class<?> cl = Class.forName(name);
			printClass(cl);
			for (Method m : cl.getDeclaredMethods())
				printMethod(m);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	
	public static void printClass(Class<?> cl) {
		System.out.print(cl);
		printTypes(cl.getTypeParameters(), "<", ", ", ">", true);
		Type sc = cl.getGenericSuperclass();
		if (sc != null) {
			System.out.print(" extends ");
			printType(sc, false);
		}
		printTypes(cl.getGenericInterfaces(), " implements ", ", ", "", false);
		System.out.println();
	}
	
	public static void printMethod(Method m) {
		String name = m.getName();
		System.out.print(Modifier.toString(m.getModifiers()));
		System.out.print(" ");
		printTypes(m.getTypeParameters(), "<", ", ", "> ", true);
		
		printType(m.getGenericReturnType(), false);
		System.out.print(" ");
		System.out.print(name);
		System.out.print("(");
		printTypes(m.getGenericParameterTypes(), "", ", ", "", false);
		System.out.println(")");
	}
	
	public static void printTypes(Type[] types, String pre, String sep, String suf,
			boolean isDefinition) {
		if (pre.equals(" extends ") && Arrays.equals(types, new Type[]{Object.class})) return;
		if (types.length > 0) System.out.print(pre);
		for (int i = 0; i < types.length; i++) {
			if (i > 0) System.out.print(sep);
			printType(types[i], isDefinition);
		}
		if (types.length > 0) System.out.print(suf);
	}
	
	public static void printType(Type type, boolean isDefinition) {
		if (type instanceof Class) {
			Class<?> t = (Class<?>) type;
			System.out.print(t.getName());
		} else if (type instanceof TypeVariable) {
			TypeVariable<?> t = (TypeVariable<?>) type;
			System.out.print(t.getName());
			if (isDefinition)
				printTypes(t.getBounds(), " extends ", " & ", "", false);
		} else if (type instanceof WildcardType) {
			WildcardType t = (WildcardType) type;
			System.out.print("?");
			printTypes(t.getUpperBounds(), " extends ", " & ", "", false);
			printTypes(t.getLowerBounds(), " super ", " & ", "", false);
		} else if (type instanceof ParameterizedType) {
			ParameterizedType t = (ParameterizedType) type;
			Type owner = t.getOwnerType();
			if (owner != null) {
				printType(owner, false);
				System.out.print(".");
			}
			printType(t.getRawType(), false);
			printTypes(t.getActualTypeArguments(), "<", ", ", ">", false);
		} else if (type instanceof GenericArrayType) {
			GenericArrayType t = (GenericArrayType) type;
			System.out.print("");
			printType(t.getGenericComponentType(), isDefinition);
			System.out.print("[]");
		}
	}
}
